// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/threading/thread_restrictions.h"

#if ENABLE_THREAD_RESTRICTIONS

#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/threading/thread_local.h"

namespace base {

namespace {

    LazyInstance<ThreadLocalBoolean>::Leaky
        g_io_disallowed
        = LAZY_INSTANCE_INITIALIZER;

    LazyInstance<ThreadLocalBoolean>::Leaky
        g_singleton_disallowed
        = LAZY_INSTANCE_INITIALIZER;

    LazyInstance<ThreadLocalBoolean>::Leaky
        g_wait_disallowed
        = LAZY_INSTANCE_INITIALIZER;

} // namespace

// static
bool ThreadRestrictions::SetIOAllowed(bool allowed)
{
    bool previous_disallowed = g_io_disallowed.Get().Get();
    g_io_disallowed.Get().Set(!allowed);
    return !previous_disallowed;
}

// static
void ThreadRestrictions::AssertIOAllowed()
{
    if (g_io_disallowed.Get().Get()) {
        LOG(FATAL) << "Function marked as IO-only was called from a thread that "
                      "disallows IO!  If this thread really should be allowed to "
                      "make IO calls, adjust the call to "
                      "base::ThreadRestrictions::SetIOAllowed() in this thread's "
                      "startup.";
    }
}

// static
bool ThreadRestrictions::SetSingletonAllowed(bool allowed)
{
    bool previous_disallowed = g_singleton_disallowed.Get().Get();
    g_singleton_disallowed.Get().Set(!allowed);
    return !previous_disallowed;
}

// static
void ThreadRestrictions::AssertSingletonAllowed()
{
    if (g_singleton_disallowed.Get().Get()) {
        LOG(FATAL) << "LazyInstance/Singleton is not allowed to be used on this "
                   << "thread.  Most likely it's because this thread is not "
                   << "joinable, so AtExitManager may have deleted the object "
                   << "on shutdown, leading to a potential shutdown crash.";
    }
}

// static
void ThreadRestrictions::DisallowWaiting()
{
    g_wait_disallowed.Get().Set(true);
}

// static
void ThreadRestrictions::AssertWaitAllowed()
{
    if (g_wait_disallowed.Get().Get()) {
        LOG(FATAL) << "Waiting is not allowed to be used on this thread to prevent "
                   << "jank and deadlock.";
    }
}

bool ThreadRestrictions::SetWaitAllowed(bool allowed)
{
    bool previous_disallowed = g_wait_disallowed.Get().Get();
    g_wait_disallowed.Get().Set(!allowed);
    return !previous_disallowed;
}

} // namespace base

#endif // ENABLE_THREAD_RESTRICTIONS
